Yes, that's right if it pressed on the 3rd cranial nerve. I just threw it in there as another pathology that could affect pupils - they can occur in other locations also with other symptoms and other effects on pupils. Just one of many possible causes of pupillary abnormalities.
MJK MD
Hi there thanks Dr Kutryb, i was wondering if you could tell help me further i was under the impression that an aneurysm would cause one of the pupils to enlarge/dilate and not react/contract well to light wheras my pupils both react briskly to light and also enlarge and contract normally except the smaller pupil does not dilate as quickly or as much in dark,thanks paolo.
Also, anisocoria is tougher to pin down sometimes than you might think. I would be sure you had an experienced neuro-ophthalmologist diagnose which pupil is abnormal before you assume which one is. If well trained they can pick up subtle differences that a neurologist wouldn't notice. So being contrarian - perhaps the abnormal pupil didn't change - just fooled untrained examiners possibly?
MJK MD
Very interesting case - and very difficult to diagnose the cause. It sounds like you have undergone and extensive workup and I don't have much to add. Thankfully, you don't appear to have a tumor or aneurysm or carotid dissection so that is a major blessing. I would concentrate on that good news for now. I've dealt with a few very mysterious cases of Horner's Syndrome and sometimes never find the cause. Thank God, no serious problems found at this point.
MJK MD